Circulating matrix metalloproteinase-1 and -3 in patients with an acute coronary syndrome.

To elucidate the diagnostic value of serum matrix metalloproteinase (MMP) levels, we measured MMP-1 and MMP-3 by a 1-step sandwich enzyme immunoassay. The transcardiac gradients of both MMPs were greater in patients with unstable angina and acute myocardial infarction than in patients with stable effort angina or control patients. Serum MMP levels appear to be a marker of plaque instability in patients with acute coronary syndrome.